Firesheep is a Firefox extension that makes it easier to steal logins and take over social media and email accounts after users log in from a WiFi hotspot or even their own unprotected network. Zscaler researchers have created, and are now offering to every consumer, a free Firefox plugin called BlackSheep, which serves as a counter-measure. BlackSheep combats Firesheep by monitoring traffic and then alerting users if Firesheep is being used on the network. BlackSheep does this by dropping ‘fake’ session ID information on the wire and then monitors traffic to see if it has been hijacked.